Blood maintains its fluidity in blood vessels and flows therethrough. However, once bleeding occurs, a coagulation factor present in plasma or platelets is activated in a chain reaction, and fibrinogen in plasma is converted into fibrin, and the fibrin is deposited, whereby bleeding is arrested. Such blood coagulation includes an extrinsic one in which blood leaking outside the blood vessel coagulates and an intrinsic one in which blood coagulates in the blood vessel. The measurement items with respect to blood coagulability (coagulation time) include a prothrombin time (PT) in an extrinsic blood coagulation reaction test, an activated partial thromboplastin time (APTT) and a fibrinogen level (Fbg) in an intrinsic blood coagulation reaction test, and the like.
All these items are measured by detecting fibrin deposited by adding a reagent to start coagulation using an optical, physical, or electrical technique. As the method using an optical technique, there is known a method in which light is irradiated onto a reaction solution, and fibrin deposited in the reaction solution is detected as a change in the intensity of scattered light or transmitted light over time, whereby the time when fibrin starts to deposit is calculated. Further, in the field of blood coagulation-fibrinolysis test, other than the measurement of a blood coagulation time, also the measurement of a coagulation factor and the measurement of coagulation-fibrinolysis markers are also included. In the measurement of a coagulation factor, the measurement is performed mainly in a blood coagulation time measurement section, however, coagulation-fibrinolysis markers are analyzed using an absorptiometer by a synthetic substrate method, a latex agglutination method, or the like.
In an automatic blood coagulation analyzer represented by PTL 1, it is necessary to report the result of the measurement of a coagulation time in 0.1 second unit and it is necessary to perform continuous photometry, and since it is impossible to recycle a reaction container by cleaning when a reaction solution is coagulated, the reaction is performed in an independent photometric port, and the reaction container is disposable. Further, the coagulation time is as short as several seconds, and therefore, it is necessary that the temperature should reach 37° C. which is the temperature condition required for the reaction immediately after a sample and a reagent are mixed with each other. The reagent is generally stored in a reagent cool box at 5 to 10° C., and in order to heat the reagent, a reagent dispensing mechanism for a reagent for use in the item of a coagulation time is provided with a reagent heating function.